Shoe upper provided with protective spray cover and method for forming same



P 1953 c G NEWTON JR 2,651,856

SHOE UPPER P fovI'DEn WITH PROTECTIVE SPRAY COVER AND METHOD FOR FORMING SAME Filed Nov. 19,, 1948 Jill/622101" Charles 6 Newton, Jr: By his Azzorncf Patented Sept. 15 1953 SHOE nPPEmmovmEn .WITRPRQTECfivE AX covert-AND METHOD FOR FORM- ING SAME j 1%, to United Shoe Machinery Corporation;

Fle'- innomnN; J2; a corporation of'New' Jersey xfisiicstfofinttmber 19, 1948; strains. 61,044

This invention relatsto temporaryprotective covering of articles and particularly to attemporarily covered shoe and methodtof rormmg such cover for the prevention of injury to the shoe during shoemaking a t In the manufacture of shoes; thef displ'ayjs'ilrf faces of parts of the" shoe u'pterf; which ni'ay be of fabric and/or le'a'th'r; be stained during the sh'oemaking op v practice of providingte'rhporary prot ctivec'overs over the shoe upper has beeneinployed'inmany instances, particularly with'light colored orwhit'e shoe uppers. These c'ov have been of two types, namely preformed cdver's"sueli as paper and covers formed by" spraying a" coating of a substance such as rubber 1atex on th'uppef.

An improved form of coating tor-shoe uppers, disclosed in the patent to John J. Broph'y 2,396,313, dated lflalch 1 2, 194 6, involves the spraying on a shoe upper'of a solution of a'vinyl resin and plasticizer to forth a shoeeover; In many cases thorougm satis'ta'ctory" protective coatings are formed. However; extreme care must be observed with certain types of sho'e'iip per materials to prevent harm to the shoe upper from the material sprayed thereon.

It is required. of protective shbecevr's" that they have toughness to" With'stth'd'the shoemaking operations and that th I V lightly to the material's'of the sh'de'llbfir'bilt'ribt so strongly that the cover is diificult to'remove. Notwithstanding care taken in the" control of conditions of spraying, ithasbeen foun'd that, with certain of the shoe material'scovered,-pre vious coating compositions have harmed the finish of theshoe or dissolved" color from" the shoe surface so that the"shoe,after removalof the cover, has presented an uneven" spotty or streaky appearance. To" a" considerable extent this eiiect on the color of the shoe" surface has been due to the presence of plasticizemvvhich has been required to give the desired-physical characteristics to theshoe cover; and to the action of the solvents. These solvents-which are satisfifactory solvents for vinyl resins are relatively polar and as such display an'affinity for like substances such as dyestuffs and certain of the finishes normally employed. It has mosses" observed with certain shoe" materials, that the migration of the plasticize'r fr'o'ifi theboat'ingto the surfa'c'eof the'shoeupperwhenthecovr is -lefton the shoe upper for extende'd periods of-time will cause an undesirable in'c'rease in the strength of the bond between th'e shoe --upper in the shoe 'cover whicl'i lias mad' it' -difieult to re"- move such covers-mmthe-shoes;

I It is a1 featureof thepresefitiinvention to pro-' vide a temporary protective covering on" shoes which does not attack the finish ofthe shoe us per and does not tend to develop 'exc'essivebon'd. strength to the surface of the shoe upper upon: nd n or V Referring to eaeeomsanying drawings;

Fi .1 1 jsp 'ct an e P i iwh I h may be employed in practieing thenie'thod of the: present'invention; and a H H Fig. 2' is an" elevationof' afla'st'ed shoe; tothe: upper of which there h teen applied af p r o :getive coating according to the'preseiitinvem- .I shar e-m s readilyjrernovable; to sheet of fibrouschara'ot er; protective covering for articles such may be formed on the surface ofs h by spraying an urip 1asticited cop er'of sty rene with isobutylene orf butadiene on saidsur faces. The coating doesriotattackthe color or finish of the'surface'nor does"ittendtojdevelop an objectionablyhigh bond qfthe-suiface-updn long standing. This esu i considered Inost unusual'sinoe, ace ing toiall prior developr'nents; it has"beerifirnportant'to employ as 'a base, a} resin of high strength and" to' ixiipart to? such base the necessaryjfle'ziibi-lity andexteiisibility' by addition OfI a' plasticizerf thereto; Hence; it 'vva s not expected that a" spray covering' coiild be formed offa material possessing" inunm'odified state the necessary: physical characteristics needed to' give protection to the shoe upper and at the same time provide a lightly adhering film readily removable as" a" unitary" sheet frorn substantially all of the ety? of shoe upiriei' mate; rials encountered. further observed that spray compositions of these lcop'olymers exhibit on spraying a strong webbing effect. That is, the material as; s pray'edb forms Webs or fibers elation on the i. l ive ef a liil her j q t a rfl permitsa gi ve'naniount of spray material tojbeusedtopover a greater area than wouldflbe theflcaservvitli c dsitiohs not forming webs. Alsogaps" and-irregularitiesdn a silrfa'ce to be covefed ar'e readily bridged of styrene have been found useful. Preferred styrene, isobutylene copolymers comprise from 50 to 60% of styrene; and preferred styrene, butadiene copolymers comprise from 50 to 70% of styrene. A copolymer which is particularly satisfactory consists of 60% styrene and 40% isobutylene and has an intrinsic viscosity of from 0.7 to 0.9, a durometer hardness (Shore) of from 80 to 90, and a Williams plasticity and recovery (70 C. kg. load) of 380-20. It has an ultimate elongation percentage of from 250 to 300, and a tensile strength of 1500 to 2500 lbs. per square inch. A similar material which is very satisfactory consists of a copolymer of 50% styrene and 50% isobutylene which has an intrinsic viscosity of 0.7 to 0.8, a durometer hardness (Shore) of 50 to 63, a Williams plasticity and recovery (70 C.5 kg. load) of 159'7, a tensile strength of from 1000 to 1500 lbs. per square inch, and an ultimate elongation in percentage of from 450 to 500. Other materials which can be used include a copolymer comprising 70% styrene and 30% butadiene which has a specific gravity of 1.03.

These copolymers are dissolved in a highly volatile organic solvent to form compositions which may be sprayed according to the method of the present invention to form highly satisfactory temporary protective covers. It is desired although not always necessary that the boiling point range of the solvent or solvent blend be such that at least 50% will be evaporated at temperatures below 50 C. Suitable solvents include chlorinated hydrocarbons such as methylene chloride and carbon tetrachloride, aliphatic hydrocarbons such as n-pentane and the amylenes, and aromatic hydrocarbons such as benzene.

These solvents may be employed either alone or in combination with others of the above solvents which are miscible. For example, a highly satisfactory solvent blend for the isobutylenestyrene copolymer will comprise a mixture of n-pentane and carbon tetrachloride containing 50 to 90% of n-pentane.

The coating compositions may comprise from to 40% of the copolymer in the volatile organic solvent. It is preferred to use coating compositions in the higher range of concentrations of copolymer and a particularly satisfactory coating composition comprises a solution of 35% of the copolymer of 60% styrene and 40% isobutylene in a mixed solvent comprising equal quantities by weight of n-pentane and carbon tetrachloride.

The coating compositions may be sprayed on articles such as shoe uppers by any convenient spray apparatus. The apparatus shown in Fig. l, which may be used in forming a temporary protective covering on shoes is similar to commercially available spray coating apparatus and comprises a generally rectangular compartment I0 open at one side and an exhaust vent H2 in the top, adjacent to the back side for withdrawal of solvent vapors. A support I4 for a lasted shoe upper l6 which is to be coated is pivotally carried by a bracket l8 which is secured to a wall of the compartment l0, said support being so constructed that the shoe may be swung and turned in various paths so as to permit all localities on the upper of the shoe to be exposed to a spray which emerges from the spray gun 22. As shown, the gun 22 is suspended by means of a spring loaded pulley attachment 24 from the top side 26 of the compartment. In coating the upper of a shoe IS the operator holds the spray gun 22 in one hand while with the other he manipulates the support M by means of a handle 28 and causes the spray to travel over the upper. Depending upon the nature of the upper of the shoe and of thematerial of which the spray is formed,

the spray may be caused, if desired, to travel a plurality of times over the upper so as to build up a thin but uniform protective coating 29 (see Fig. 2). It has been found desirable to form coatings which have a thickness of from 0.005 to 0.020 when dry.

Leading into the spray gun 22 are two flexible w pipes 30 and 32 which conduct, respectively, the

viscous spray composition and the compressed air tothe gun 22.

There is provided a container 34 from which the resinous material is supplied to the flexible pipe 30. A safety valve 36 is provided at the top of the container 34.

Compressed air from a source of supply (not shown) passes through a pipe 38, and then through an air purifier 40. From the purifier the air passes to a T 42 where it divides, and part passes through a pressure reducer 44 and thence through a flexible pipe 46 to the top of the container 34, while another part passes through a second pressure reducer 48 to the flexible pipe 32 and thence to the spray gun 22. In the operation of the apparatus the air is ordinarily supplied to the spray gun 22 at a pressure of from 20 to pounds per square inch and to the container 34 at from 20 to 80 pounds per square inch.

The apparatus which has been thus briefly described forms no part of the present invention and any suitable apparatus may be employed.

The following examples of spray compositions which may be employed according to the present invention to form temporary protective covers on articles such as shoes are given to aid in understanding the invention. It is to be understood that the invention is not limited to the particular ingredients or proportions employed in the examples:

Example I Parts by weight Copolymer of 60% styrene and 40% of isobutylene 146.5 n-Pentane Carbon tetrachloride 135 The copolymer material was dissolved in the mixture of n-pentane and carbon tetrachloride and the solution introduced into the coating material container of a spray apparatus such as that shown in vFig. 1. A lasted shoe upper was mounted on the support M of the apparatus and was sprayed with the above coating composition using a pressure of about 40 lbs. in the air line 32 and a pressure of about 20 lbs. on the material in the container 34. A covering was rapidly formed on the shoe and this cover was strong, flexible, and lightly adherent to the shoe upper and readily stripped off from the shoe after completion of shoemaking operations.

Example II Parts by weight Copolymer of 50% styrene and 50% of isobutylene 118.4 n-Amylene Carbon tetrachloride 140 Example III Parts by weight Copolymer of 70% styrene and 30% of butadiene 100 Benzene 200 Carbon tetrachloride 200 This material was sprayed on a shoe upper according to the procedure outlined in Fig. 1 and formed a satisfactory cover which possessed strength requisite to avoid rupture during further shoemaking operations and which was readily removable from the shoe after completion.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A method for forming on the surface of an article a tough, strong, lightly adherent film serving as a removable temporary protective cover which comprises injectinga coating solution into a high pressure, high velocity air blast to form a spray of fine droplets of the coating solu tion, and directing said spray of coating solution at the surface of the article, the coating solution comprising a film forming component and a solvent therefor, said film forming component consisting of an unplasticized copolymer of from 40% to 75% by weight of styrene with from 60% to 25% by weight of a member selected from the group consisting of isobutylene and butadiene, and said solvent comprising a highly volatile nonpolar organic solvent medium for the copolymer having a boiling range such that at least 50% of the solvent will boil below 50 C., the copolymer being present to the extent of from to 40% by weight of the solution.

2. A method for forming on the surface of an article a tough, strong, lighly adherent film serving as a removable temporary protective cover which comprises injecting a coating solution into a high pressure, high velocity air blast to form a spray of fine droplets of the coating solution, and directing said spray of coating solution at the surface of the article, the coatin solution comprising a film forming component and a solvent therefor, said film forming component consisting of an unplasticized copolymer of from 50% to 60% by weight of styrene withfrom 50% to 40% by weight of isobutylene, and said solvent comprising a highly volatile nonpolar organic solvent medium for the copolymer having a boiling range such that at least 50% of the solvent will boil below 50 C., the copolymer being present to the extent of from 15% to 40% by weight of the solution.

3. A method for forming on the surface of an article a tough, strong, lightly adherent film serving as a removable temporary protective cover which comprises injecting a coatingsolution into a high pressure, high velocity air blast to form a spray of fine droplets of the coating solution, and directing said spray of coating solution at the surface of the article, the coating solution comprising a film forming component and a solvent therefor, said film forming component consisting of an unplasticized copolymer of from 50% to by weight of styrene with from 50% to 30% by weight of butadiene, and said solvent comprising a highly volatile nonpolar organic solvent medium for the copolymer having a boilingrange such that at least 50% of the solvent will boil below 50 C., the copolymer being present to the extent of from 15% to 40% by weight of the solution.

4. The combination of a shoe upper and a tough, strong, temporary protective covering lightly adhering to said upper, said covering being formed by the process of claim 1 from a coating solution and being composed of partially coalesced fibers, said fibers cohering so strongly that the coverin may be readily stripped from the upper as a sheet.

5. The method as claimed in claim 2 wherein the highly volatile organic liquid solvent for the copolymer comprises from 50 to n-pentane and from 10% to 50% carbon tetrachloride.

6. The method as claimed in claim 3 wherein the highly volatile organic liquid solvent for the copolymer comprises a solvent blend including at least 50% benzene.

'7. The combination of a shoe upper and a tough, strong, temporary protective covering lightly adhering to said upper, said covering being formed by the process of claim 2 from a coating solution and being composed of partially coalesced fibers, said fibers cohering so strongly that the covering may be readily stripped from the upper as a sheet.

8. The combination of a shoe upper and a tough, strong, temporary protective covering lightly adhering to said upper, said covering being formed by the process of claim 3 from a coating solution and being composed of partially coalesced fibers, said fibers cohering so strongly that the cover may be readily stripped from the upper as a sheet.

9. The method as claimed in claim 2 wherein the highly volatile organic liquid solvent for the copolymer comprises a solvent blend including at least 50% n-pentane.

10. The method as claimed in claim 2 wherein the highly volatile organic liquid solvent for the copolymer comprises a solvent blend including at least 50% n-amylene.

CHARLES G. NEWTON, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,317,858 Soday Apr. 2'7, 1943 2,404,313 Rodman July 16, 1946 2,431,684 Brophy Dec. 2, 1947 2,459,164 Holst Jan. 18, 1949 

1. A METHOD FOR FORMING ON THE SURFACE OF AN ARTICLE A TOUGH, STRONG, LIGHTLY ADHERENT FILM SERVING AS A REMOVABLE TEMPORARY PROTECTIVE COVER WHICH COMPRISES INJECTING A COATING SOLUTION INTO A HIGH PRESSURE, HIGH VELOCITY AIR BLAST TO FORM A SPRAY OF FINE DROPLETS OF THE COATING SOLUTION, AND DIRECTING SAID SPRAY OF COATING SOLUTION AT THE SURFACE OF THE ARTICLE, THE COATING SOLUTION COMPRISING A FILM FORMING COMPONENT AND A SOLVENT THEREFOR, SAID FILM FORMING COMPONENT CONSISTING OF AN UNPLASTICIZED COPOLYMER OF FROM 40% TO 75% BY WEIGHT OF STYRENE WITH FROM 60% TO 25% BY WEIGHT OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF ISOBUTYLENE AND BUTADIENE, AND SAID SOLVENT COMPRISING A HIGHLY VOLATILE NONPOLAR ORGANIC SOLVENT MEDIUM FOR THE COPOLYMER HAVING A BOILING RANGE SUCH THAT AT LEAST 50% OF THE SOLVENT WILL BOIL BELOW 50* C., THE COPOLYMER BEING PRESENT TO THE EXTENT OF FROM 15% TO 40% BY WEIGHT OF THE SOLUTION. 